Ukrainian President Petro Poroshenko said Monday that his country will be able to meet the conditions to apply for European Union membership within five years, while European Union officials rejected his request call for an EU peace-keeping mission to eastern Ukraine, where a year of fighting between government and Russia-backed separatist forces has killed more than 6,100 people.

"We are ambitious in our plans and our belief, and that's why we declare that within five years we will provide effective implementation of the [EU] association agreement and meet conditions required to apply for membership in the European Union," Poroshenko said at the start of a summit with top EU officials in Kyiv.

The Ukrainian president told reporters after meeting Monday with EU President Donald Tusk and EU Commission President Jean-Claude Juncker that Ukraine had "won the right" to join the EU during the "Revolution of Dignity" — a reference to last year's ouster of his pro-Moscow predecessor, Viktor Yanukovych. Poroshenko said Ukraine is currently defending that right in what he called a "war against the Russian aggression."

Yanukovych's decision not to sign a political and free trade association agreement with the European Union helped spark mass demonstrations against him. Ukraine signed the EU association agreement last year after his ouster.

President Poroshenko also called Monday for "the deployment of a European Union operation" to help establish "the proper security conditions" for fulfilling the cease-fire agreement signed in February by Ukrainian government and separatist representatives.

EU President Tusk said the bloc would send a civilian "assessment" mission to explore ways to assist Ukraine, but that it would be "impossible" to send a "military mission.”

Meanwhile, a Ukrainian military spokesman said Monday that the rebels in eastern Ukraine are intensifying attacks in violation of the cease-fire agreement.

Oleksandr Motuzyanyk reported that one Ukrainian serviceman was killed and three wounded in fighting over the previous 24 hours. On Sunday, one soldier was killed and seven wounded in eastern Ukraine, according to the government.

Monitors with the Organization for Security and Cooperation in Europe (OSCE) reported observing intense fighting Sunday near the village of Shyrokyne, located just a few kilometers east of the strategic southeastern Ukrainian port city of Mariupol.